Week -2

Ans-1:- Simulink model of Doorbell using solenoid

In order to model this system, following blocks has been used:

Pulse generator for switch operation.

DC battery Source for solenoid coil excitation.

Solenoid Block for motion of Plunger.

Translational Motion Sensor to observe the motion.

Scope to observe the Output response w.r.t. applied Input.

Simulink model is shown here:

Output Waveform:

Ans-2: Use a thermistor to sense the temperature of a heater & turn on or turn off the fan

For Modelling this system I have used following blocks:

Repeating Sequence Stair, in order to feed the temperature conditions to the Thermistor.

Controlled Temperature Source to maintain a controlled temperature difference regardless of the heat flow rate.

Thermistor Block

Voltage Sensor to sense the voltage across the resistance

Switch to compare the conditions of threshold.

Display and Scope.

Note: Signal Builder Block can also be used to feed the temperature conditions.

The Model is given here:

The output of the model represents that the switch is ON during the time duration of 10-30 seconds when the temperature is 27 degree Celcius.

Temperature source:

20 °C from 0 to 10 seconds,

27 °C from 10 to 30 seconds,

23 °C from 30 to 50 seconds

Fan conditions: ON if the temperature above 25 °C, OFF otherwise